On The Resolution of Ultrasensitive Optical Resonator-Based Biosensors: The Effects of Fabrication Parameters

Optical resonators-based biosensors are high sensitive systems for biological samples detection and by functionalizing the resonator surface, they can identify a specific target as well. The fabrication and surface functionalization processes of the resonator can cause unevenness on its surface and create asymmetry in the cavity structure. In this paper, we have investigated the light scattering loss from the resonator surface as well as the resonant power profile broadening, considering the effects of surface roughness and asymmetry of resonator. The results show that the presence of imperfections in the resonator structure, increases the optical losses and causes mode splitting which result in reduction of the resolution of the sensor. Increasing the surface roughness provides for the better overlap of resonant mode with the biolayer which results in increasing the sensor sensitivity, while reducing the resolution of the sensor due to reduction of cavity quality factor. These results are useful in designing of ultra-sensitive optical biosensors.

Keywords:

Aspheric , Biosensors , Detection limit , Index sensing , Optical resonators , Surface roughness